Method for providing power plant maintenance services

ABSTRACT

An objective is to quickly provide appropriate maintenance services at low costs during routine inspection procedures and/or upon occurrence of abnormal events at thermal power plants or stations. In a thermal power plant maintenance system comprising a control device  1  for control of operation conditions and process amounts of plant equipment and a maintenance tool  2  operatively linked to the control device  1  via a network  7  for performing maintenance of a controlling controller  11  as built in the control device  1 , the system further comprises a remote maintenance device  3  that executes similar functions to those offered by the maintenance tool  2  for bidirectionally transferring plant data along with data concerning the controlling controller  11 &#39;s status via a communications line  8  between the maintenance tool  2  and the remote maintenance device  3  to thereby provide maintenance services of the thermal power plant of interest.

CROSS REFERENCE TO RELATED APPLICATIONS

This is a continuation of application Ser. No. 10/458,379 filed 11 Jun.2003, now U.S. Pat. No. 6,768,970 which is a continuation of applicationSer. No. 09/793,947 filed Feb. 27, 2001, now U.S. Pat. No. 6,665,635 thecontent of which is incorporated herein by reference it its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to a method for providingthermal power plant maintenance services and, more particularly, to athermal power plant maintenance service provision method adaptable foruse in routine inspection procedures and/or upon occurrence ofabnormality or aberrant phenomena.

2. Description of The Prior Art

In thermal power stations or plants, in cases where certainabnormalities occur during routine inspection and/or in the in-use stateor alternatively monitoring is especially required in specific eventssuch as upon start-up/shut-down of a unit, some works should be requiredincluding but not limited to control system adjustment, searching for acause(s) of abnormality, making up a countermeasure, and preparation ofa search report. Traditionally, in regard to such maintenance services,an engineer working for a manufacturer, who has received a request froma client (thermal power plant), goes to the power plant for completesuch tasks in situ.

The prior art suffers from a problem as to the difficulty of expeditingthe cause research procedure for obstruction recovery when abnormalitiesoccur during operation due to the fact that a time is taken for themaker's engineer to actually arrive at the power station. Anotherproblem faced with the prior art is that the engineer's working at thereal cite accompanies extra costs including a visiting expense,resulting in an increase in inspection costs as a whole.

SUMMARY OF THE INVENTION

It is therefore an object of the present invention to provide a new andimproved thermal power plant maintenance service providing methodcapable of offering prompt and adequate maintenance service abilitiesduring routine inspection and upon occurrence of abnormalities at athermal power station while reducing costs required therefor.

To attain the foregoing object, the present invention provides a thermalpower plant maintenance service provision method adaptable for use witha system including a remote maintenance device for execution offunctions similar to those offered by a maintenance tool, the methodincluding the step of permitting a maintenance service providing personto makes use of the remote maintenance device as linked to themaintenance tool via communications lines for bidirectionallytransferring plant data and data as to a present state of a controllingcontroller between the maintenance tool and the remote maintenancedevice to thereby provide thermal power plant maintenance services.

As explained above, according to the present invention, it becomespossible, by comprising remote maintenance apparatus for execution ofsimilar functions to those offered by the maintenance tool while at thesame time letting the maintenance service provider employ the remotemaintenance apparatus as linked via communications lines to themaintenance tool in the power station, to remotely provide any requiredmaintenance services including but not limited to test data summary andevaluation results during routine inspection procedures and/or searchand investigation results in abnormality occurrence events, which inturn makes it possible to provide prompt and proper maintenance servicesat low costs in routine inspection events and/or abnormality occurrenceevents, thus enabling improvement in quality of maintenance services.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram showing an overall configuration of a system forexplanation of a thermal power plant maintenance service providingmethod in accordance with one preferred embodiment of the presentinvention.

FIG. 2 is a function diagram of a maintenance tool of this invention.

FIG. 3 is a function diagram of a remote maintenance device of theinvention.

FIG. 4 is a flow diagram of a routine inspection service of theinvention.

FIG. 5 is a diagram showing a sequence of examples of an operationon-screen display for editing and analysis of static characteristicstest data of the invention.

FIG. 6 is a diagram showing a sequence of examples of an operationdisplay image for editing and analysis of dynamic characteristics testdata of the invention.

FIG. 7 is a diagram showing a sequence of exemplary operation displayimages for editing and analysis of load change test data of theinvention.

FIG. 8 is a diagram showing an exemplary operation display forpreparation of control parameter change instruction data of theinvention.

FIG. 9 is a diagram showing a sequence of some exemplary operationdisplay images for preparation of static characteristics test report ofthe invention.

FIG. 10 is a diagram showing a sequence of exemplary operation displayimages for preparation of dynamic characteristics test report of theinvention.

FIG. 11 is a diagram showing a sequence of exemplary operation displaysfor preparation of load change test report of the invention.

FIG. 12 is a flow diagram of a service upon occurrence of an operationfailure in the controller of the invention.

FIG. 13 is a diagram showing a sequence of exemplary operation displayimages for error log information research and analysis of the invention.

FIG. 14 is a diagram showing a sequence of exemplary operation displaysfor preparation of recovery work guidance data of the invention.

FIG. 15 is a flow diagram of a service in control failure events of theinvention.

FIG. 16 is a diagram showing a sequence of exemplary operation displaysfor preparation of a control failure research request of the invention.

FIG. 17 is a diagram showing a sequence of exemplary operation displaysfor analysis of control failure event data of the invention.

FIG. 18 is a diagram showing a sequence of exemplary an operationdisplays for preparation of a control failure search report of theinvention.

FIG. 19 is a flow diagram of an ordinary event service of the invention.

FIG. 20 is a diagram showing a sequence of exemplary operation displaysfor preparation of a monitor search request of the invention.

FIG. 21 is a diagram showing a sequence of exemplary operation displaysfor analysis of data in ordinary event data of the invention.

FIG. 22 is a diagram showing a sequence of exemplary operation displaysfor preparation of a monitor search report of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

One preferred embodiment of the present invention will now be explainedwith reference to the accompanying drawings below.

FIG. 1 depicts an overall system configuration for explanation of athermal power plant service provision method in accordance with onepreferred embodiment of the instant invention. This system comprises apower station side facility, which includes a control device 1containing therein a built-in controlling controller 11 and a processsignal input/output device (transfer device) 12, and a maintenance tool2 for performing maintenance of the control device 1 and datasave/storage of process signals or the like, which tool is operativelyassociated with a signal transmitter 4 and thermocouple 5 for sendingforth electrical signals indicative of process amounts such as apressure and temperature or else toward the control device 1 through aPI/O device 13, an operation end 6 such as a valve and/or a controldrive being operatively responsive to receipt of more than one controlsignal from the control device 1 for controlling the process amountssuch as pressure and temperature or the like so that each stays at aprespecified value, wherein the control device 1 and the maintenancetool 2 are operatively connected to each other via a unit network 7. Themaintenance tool 2 consists essentially of a central processing device21, a communication device 22, a monitor 23, and a transfer device 24.Although not specifically depicted in FIG. 1, the unit network 7 isactually connected also to a controlling computer and a CRT operationapparatus or the like for use as an operator's operation terminal inaddition to the control device 1 and maintenance tool 2. The system ofFIG. 1 also comprises a maintenance service provider side facility,which includes a remote maintenance device 3 with functions foranalyzation and editing of data as sent from the maintenance tool 2 onthe power station side and those for a variety of kinds of services.

The maintenance tool 2 on the power station side and the remotemaintenance device 3 on the maintenance service provider side areoperatively connected together via a public communication line 8. Theremote maintenance device 3 consists essentially of a central processordevice 31, communication device 32, and monitor 33. Optionally themaintenance tool 2 and remote maintenance device 3 may alternatively beconnected together via dedicated or “private” communication lines otherthan public communications lines.

Functionality and operation of each device will next be set forth below.

As shown in FIG. 1, the control device 1 is constituted from thecontrolling controller 11 and transfer device 12 plus PI/O device 13 andis operable to perform, based on programs prestored in a memory withinthe controlling controller 11, control processing of process signalsindicative of pressures and temperatures as input from the transmitter 4and thermocouple 5 via the PI/O device 13 and those signals coming fromother control devices as input via the transfer device 12 and unitnetwork 7 to thereby output its control processing results toward theoperation end 6 through the PI/O device 13 for equipment control oralternatively output such results to other control devices and themaintenance tool 2 via the transfer device 12 and unit network 7.

As shown in FIG. 1 the maintenance tool 2 is configured from the centralprocessor device 21, communication device 22, monitor 23, and transferdevice 24.

Functionality and operation of the maintenance tool 2 are shown in FIG.2. At the maintenance tool 2 an input device (not shown) such as akeyboard or a pointing device called “mouse” is used to create and edita control operation logic chart, wherein drawing data thus produced iscompiled to generate object data, which will then be sent via thetransfer device 24 and unit network 7 toward the controlling controller11 within the control device 1 for storage into its built-in memory. Inaddition, the maintenance tool 2 also has a “parameter online tuning”function for inputting a parameter change instruction through manualoperation of the input device such as a keyboard or mouse and thenrewriting a control parameter(s) being presently stored in the memorywithin the controlling controller 11 via the transfer device 24 and unitnetwork 7 in an online fashion. Further, it has a data save/storefunction capable of inputting a signal being presently output from thecontrol device 1 via the unit network 7 and transfer device 24,temporarily storing the signal in the central processor device 21, andpermitting visual on-screen displaying of numeric values and/or trendgraphs based on an instruction from the input device such as a keyboardor mouse. Other functions of the maintenance tool 2 include an error logacquisition function for acquiring or fetching error log information assaved within the controlling controller 11 via the unit network 7 andtransfer device 24 in the event that a certain operation failure orobstruction takes place in the controlling controller 11. Additionallythe communication device 22 is operable to control communications withexternal equipment over the public communication line 8.

As shown in FIG. 1 the remote maintenance device 3 is structured fromthe central processor device 31 and communication device 32 plus monitor33. The remote maintenance device 3 offers similar functionality to thatof the maintenance tool 2, thereby allowing a person expected to providemaintenance services-say, maintenance service provider-who is at aremote location spaced far from the power station of interest toremotely execute any one of the functions of the maintenance tool 2 ofsuch power station in a remote control fashion. In addition thereto, theremote maintenance device 3 also has a function for adding any necessaryfunctions to maintenance services.

Functionality and operation of the remote maintenance device 3 are shownin FIG. 3. The remote maintenance device 3 is designed to acquire fromthe maintenance tool 2 via the public communication line 8 andcommunication device 32 over communications several data items (processsignal data, control signal data, controlling controller error log,controlling controller object data, control parameters, etc.) that themaintenance tool 2 has received from the control device 1 and then savethem at a memory device. And it edits and/or processes such data as hasbeen gained from the maintenance tool 2 and saved at the memory devicein a way conformity with the content of a maintenance service beingpresently provided. The maintenance service provider then use the remotemaintenance device 3 to thereby provide maintenance services including,but not limited to, analyzing the resultant edited/processed data forpreparation of maintenance work instruction data indicative of controlparameter modification and/or obstruction recovery works, transmittingthe data to the maintenance tool 2 via the communication device 32 andpublic communication line 8, and preparing a report to send forth reportdata toward the maintenance tool 2 via the communication device 32 andpublic communication line 8.

An explanation will next be given of a thermal power plant maintenanceservice provision method adaptable for use with illustrative embodimentof the invention. With regard to a periodic or “routine” inspectionservice as one practical example of a first maintenance service, itsservice provision method will be set forth below.

At thermal power stations, routine inspection must be done at specifiedconstant time intervals as defined under laws and regulations concerned.In routine inspection events, a trial operation known as “test run” isordinarily carried out in addition to inspection and updating adjustmentof the equipment involved. During such test run a variety of tests aredone, which typically include a static characteristics test (test forrecording and confirming various kinds of process amounts under aconstant load condition and then adjusting a control system based on thedata thus obtained), dynamic characteristics test (test for recordingand verifying the influence of process amount changes upon variousprocess amount and for adjusting the control system based on theresulting data), load change test (test for recording and confirmingvarious process amounts upon changing of the load and for adjusting thecontrol system based on the data). The “routine inspection service” issuch that these test data items thus obtained are all taken intoconsideration for investigation, wherein data analysis and test reportpreparation are expected to be remotely done by a maintenance serviceprovider.

A method for providing the “routine inspection service” is shown in aflow diagram of FIG. 4. At a power station a various kinds of tests arecarried out resulting in acquisition or “sampling” of material processamount data (pressures and temperatures or the like) and control signaldata (operation end's instruction values or else) at the maintenancetool 2 in such event. An operator or worker who is expected to act asthe maintenance service provider lets the remote maintenance device 3receive such gained data via the public communication line 8 and storeor save the data in the memory device of remote maintenance device 3.The operator then edits and analyzes the stored data at the remotemaintenance device 3. Practical contents of major process steps in theflow of FIG. 4 will be explained with reference to FIGS. 5 through 11below.

See FIG. 5, which pictorially illustrates a typical example of thesequence of on-screen visual displays for manipulation or operation bythe operator-say, “operator console” displays or “operation” displays-tobe used during the static characteristics edit/analysis processes at theremote maintenance device 3. When the operator selects an image for useas visual mnemonics or “icon” indicative of “Static CharacteristicsSummary” in a routine service menu display 9 being presently displayedon the screen of a display unit and then selects “Data Edit/Analysis” ona static characteristics summary menu display 91, the display imagechanges to visually indicate a static characteristics data edit/analysisdisplay 92. While letting a trend graph of the test data be displayed onthis screen, s/he attempts to summarize data as to material parameterswhich include, inter alia, a fuel amount, water feed amount and airamount at a certain load.

FIG. 6 shows an exemplary sequence of operation display images usedusing dynamic characteristics test data edit and analysis processes atthe remote maintenance device 3. When the operator selects an icon of“Dynamic Characteristics Test Summary” in the routine service menudisplay 9 being presently displayed on the display screen and thenselects “Data Edit/Analysis” icon in a dynamic characteristics testsummary menu display 93, a visual display 94 indicative of several dataconcerning the dynamic characteristics data edit/analysis is displayedon the screen. While viewing a test data trend graph included in thisdisplay image 94, s/he executes a task for summarization of materialdata items as to change-with-time properties of a main vapor temperatureand main vapor pressure in case a constant amount of fuel is supplied.

FIG. 7 shows an exemplary sequence of operation display images usedduring load change test data edit and analysis processes at the remotemaintenance device 3. When the operator selects an icon of “Load ChangeTest Summary” in the routine service menu display 9 and then selects“Data Edit/Analysis” in a load change test summary menu display 95, thescreen changes to visually indicate an on-screen image 95 indicative ofmaterial data as to the load change test data edit and analysis. Usingthis visual display containing therein a test data trend graph, s/hesummaries material data items as to deviation of the main vaportemperature and main vapor pressure during certain load change testprocedure.

In case the maintenance service provider's test data analyzationexecuted in this way results in more than one control parameter beingfound to be modified or updated, s/he prepares control parametermodification instruction data at the remote maintenance device 3 fortransmission to the maintenance tool 2 over the public communicationline 8.

See FIG. 8 which depicts an exemplary on-screen operation displayconcerning preparation of the control parameter modification instructiondata at the remote maintenance device 3. When the operator selects anicon of “Make Parameter Modify Instruction” in any one of the staticcharacteristics summary menu display 91, dynamic characteristics summarymenu 93 and load change test summary menu 95, the display screen changesto visually present a visual display 10 showing several data items usedfor preparation of a parameter modification/update instruction. Usingthis on-screen visual display, s/he inputs an operation macro withparameter update required and a present value thereof (a value asreceived from the maintenance tool 2 is displayed) along with anumerical value updated and then performs a transmission operation,causing the control parameter update instruction data to be sent forthtoward the maintenance tool 2 over the public communication line 8. Uponreceipt of the control parameter update instruction data, themaintenance tool 2 operates to visually display a control parameterupdate guidance in accordance with the content of such control parameterupdate instruction data on the screen of monitor 23 to thereby permit aworker who is responsible for facility adjustment at the power stationto make use of the parameter online tuning function of the maintenancetool 2 to thereby rewrite via the transfer device 24 and unit network 7in the online fashion the control parameter or parameters beingpresently stored in the memory of the controlling controller 11 indeference to the guidance displayed. Alternatively if the tuning isdirectly set up by a changeover switch or the like in the state ofallowance then the maintenance tool 2 automatically operates to rewritein online way such control parameter(s) in accordance with the contentsof the control parameter update instruction data. In addition, afterhaving analyzed the test data concerned, the maintenance serviceprovider prepares at the remote maintenance device 3 a test reportcontaining therein a data summary table and control parameter updatehistory, which will then be sent forth to the maintenance tool 2 overthe public communication line 8.

FIG. 9 shows an exemplary sequence of operation display images for useduring preparation of a static characteristics test report at the remotemaintenance device 3. When the operator selects “Static CharacteristicsSummary” icon in the routine service menu display 9 and then selects“Make Report” in the static characteristics summary menu display 91,then the screen changes to visually present a static characteristicstest report preparation display 97. Using this on-screen display themaintenance service provider attempts to prepare a report of aprespecified format in which material data items such as the fuelamount, water feed amount, air amount and the like are summarized alongwith the resultant control parameter change/update history.

FIG. 10 shows an exemplary sequence of operation display image forpreparation of a dynamic characteristics test report at the remotemaintenance device 3. When the operator selects “Dynamic CharacteristicsSummary” icon in the routine service menu display 9 and then selects“Make Report” in the dynamic characteristics summary menu display 93,the screen changes to visually indicate a dynamic characteristics testreport preparation display 98. Using this visual display the maintenanceservice provider prepares a report of a specified format in whichmaterial data items as summarized through editing and analysis ofdynamic characteristics data such as for example variation properties orthe like of the main vapor temperature and pressure in case the fuelamount is kept constant in value are indicated along with the resultantcontrol parameter change/update history.

FIG. 11 shows an exemplary sequence of operation display images forpreparation of a load change test report at the remote maintenancedevice 3. When the operator selects “Load Change Test Summary” icon inthe routine service menu display 9 and then selects “Make Report” in theload change test summary menu display 95, the screen changes to visuallyindicate a load change test report preparation display 99. Using thisvisual display the maintenance service provider prepares a report of aspecified format in which major data items as summarized through editingand analysis of load change test data such as for example variationproperties or the like of the main vapor temperature and pressure duringcertain load change test procedure are indicated along with theresultant control parameter change/update history. At the maintenancetool 2, it performs hard copy production or printing tasks with orwithout saving the report data thus received.

An explanation will next be given of a method for providing a serve inthe event that an operation failure or malfunction occurs at thecontroller-say, “controller abnormality event serve” in thedescription-as a second maintenance service example.

In the event that an operation failure or obstruction occurs at thecontrol device 1 due to certain causes, it becomes difficult for thepower plant to perform any intended operations. To avoid this, it shouldbe required to promptly perform clarification of the cause of suchobstruction creation for recovery required. In particular, thecontrolling controller 11 and PI/O device 13 and the like making up thecontrol device 1 are inherently designed to employ highly preciseelectronics parts or components with complicated control operationprograms being prestored in the memory of controlling controller 11;accordingly, upon occurrence of such obstruction, a need arises fortechnical support as to investigation by experienced engineers orspecialists. The “controller abnormality event service” is such that inthe case of occurrence of an obstruction at the control device 1, anyrequired services typically including activities for inquiring into thecause(s) and giving an instruction as to an appropriate recovery methodare done by a person who is expected to work as the maintenance serviceprovider.

See FIG. 12, which shows a process flow of such method for providing the“controller abnormality event service.” In case an error occurs at thecontrolling controller 11, an operator will become aware of thegeneration of abnormality at the control device 1, by means of an alarm.And s/he uses the error log acquisition function of the maintenance tool2 to gain error log information being presently saved within thecontrolling controller 11 via the unit network 7 and transfer device 24.Alternatively, in case an error occurs at the controlling controller 11,the maintenance tool 2 automatically operates to generate and issue asignal indicative of such error occurrence at the controlling controller11 and then send forth this signal toward the remote maintenance device3 via the communication device 22 and public communication line 8. Uponreceipt of the error occurrence signal, the remote maintenance device 3transmits an error log extraction request signal to the maintenance tool2 via the communication device 32 and public communication line 8. Whenreceiving this error log extract request signal the maintenance tool 2acquires based on the error log extraction function the error loginformation being presently saved within the controlling controller 11via the unit network 7 and transfer device 24. The error log informationgained by any one of the above schemes will then be passed to the remotemaintenance device 3 via the communication device 22 and publiccommunication line 8. The maintenance service provider attempts toinvestigate the error log information as received by the remotemaintenance device 3 for analyzation of an error cause(s)-that is,judging whether the presently occurring error is due to hardwaremalfunction or due to failures in control operation programs. Practicalcontents of the process flow of FIG. 12 will be explained in detail withreference to FIGS. 13-14 below.

FIG. 13 shows an exemplary sequence of operation display images for useduring error log information investigation/analyzation at the remotemaintenance device 3. Upon selection of “Conform Error Log” icon in acontroller abnormality event service menu display 11, the screen changesto visually indicate an error log confirmation display 111. It is thuspossible for the maintenance service provider by viewing informationdisplayed thereon to become aware of details of the error cause(s) andoperation failed parts or components. After clarification of the errorcause(s), the maintenance service provider prepares a recovery workguidance at the remote maintenance device 3, which guidance will then besent to the maintenance tool 2 over the public communication line 8.

FIG. 14 shows an exemplary sequence of operation display images for useduring recovery work guidance data preparation at the remote maintenancedevice 3. Upon selection of a “Make Recovery Guidance” icon in thecontroller abnormality event service menu display 11, the screen changesto visually indicate a recovery guidance preparation display 112. Here,the maintenance service provider prepares a recovery procedure documentwhile performing a transmission operation to transmit the recovery workguidance data to the maintenance tool 2 over the public communicationline 8. Upon receiving of the recovery work guidance data at themaintenance tool 2, recovery guidance information is visually displayedon the monitor 23 in accordance with the content of such recovery workguidance data, thus permitting more than one worker at the power stationto execute required tasks for recovery in deference to the guidance.

Next, regarding a “control failure event service” as a practical exampleof a third maintenance service, its service provision method will beexplained below.

In the power plant, unwanted control failures can take place from timeto time during operation due to the presence of some mechanical factorsand/or inappropriate control parameters, which would result for examplein generation of an alarm when a vapor pressure or temperature goes outof its tolerance range or, alternatively, result in the plant statusbecoming unstable with an increase in difficulties of continuation ofautomatic control operations. In such cases, investigation for causeclarification is required along with equipment adjustment with orwithout adjusting the control parameters of the control device 1. The“control failure event service” is such that upon occurrence of acontrol failure or malfunction, the cause clarifying investigation andadjustment for improvement are to be remotely done by the maintenanceservice provider.

FIG. 15 shows a process flow of a method for providing such “controlfailure event service.” Suppose that the vapor pressure or temperaturegoes out of the initially established allowance range during power plantoperation. In this case, let material data-e.g. the content of an alarmalong with process amount data (pressures and/or temperatures) andcontrol signal data (operation end instruction values or else)-betransmitted from the maintenance tool 2 toward the remote maintenancedevice 3 over the public communication line 8. Alternatively an operatorinputs a control failure search request at the maintenance tool 2 andthen sends forth the control failure search request and its associateddata to the remote maintenance device 3 via the public communicationline 8. Practical contents of the process flow of FIG. 15 will bedescribed with reference to FIGS. 16-18 below.

FIG. 16 shows an exemplary sequence of operation display images for useduring preparation of a control failure search request at themaintenance tool 2. Upon selection of a “Request Control Failure Search”icon in a remote maintenance request menu display 12, the screen changesto visually indicate a control failure search request display 121. Anoperator working at the power station attempts to input information asto control failure contents and failure generation date and time or thelike and then perform a data send operation, causing control failuresearch request data to be sent forth toward the remote maintenancedevice 3 via the public communication line 8. The maintenance serviceprovider saves the received data and alarm content or control failuresearch request content in the memory device of the remote maintenancedevice 3, and then analyzes such saved data at the remote maintenancedevice 3.

FIG. 17 shows an exemplary sequence of major operation displays for useduring analyzation of the control failure event data at the remotemaintenance device 3. Upon selection of a “Data Search/Analyze” icon ina control failure event service menu display 13, the screen changes tovisually indicate a control failure event data search/analyze display131. With this on-screen visual display, the maintenance serviceprovider commands to visualize a trend graph of the control failureevent data as received from the maintenance tool 2 along with thecontrol failure content and alarm content for analyzation of the controlfailure cause(s) and then careful consideration of an appropriate remedyto be taken. After completion of data analysis, the maintenance serviceprovider remotely prepares at the remote maintenance device 3 a controlfailure search report that summarizes therein modification of a controlparameter(s) or control circuitry and the control failure cause, whichreport is then sent to the maintenance tool 2 via the publiccommunication line 8.

FIG. 18 shows an exemplary sequence of operation display images for useduring preparation of the control failure search report at the remotemaintenance device 3. Upon selection of “Make Search Report” icon in thevisual display of control failure event service menu 13, the screenchanges to visually indicate a control failure search report preparationdisplay 132. With this screen image, the maintenance service providerproduces a report summarizing the control failure cause(s) and remedyplus updating of a control parameter(s) or control circuitry forimprovement of such control failure. Upon receipt of the control failuresearch report at the maintenance tool 2, a guidance for updating thecontrol parameter(s) or control circuitry is visually displayed on thescreen of the monitor 23 in accordance with the updated content of thecontrol parameter(s) or control circuitry as recited in the controlfailure search report, thus permitting an operator working at the powerstation to rewrite by use of the parameter online tuning function orcontrol operation logic edit function of the maintenance tool 2 theobject data being presently stored in the memory within the controllingcontroller 11 via the transfer device 24 and unit network 7 in deferenceto the presently displayed guidance. Alternatively, if the tuning isdirectly set by a changeover switch or the like to the state ofallowance then the maintenance tool 2 automatically operates to rewritein online way the object data in accordance with the updated content ofthe control parameter(s) or control circuitry. Additionally at themaintenance tool 2, it performs printing and/or saving tasks of thecontrol failure search report data thus received.

Next, in regard to an “ordinary event service” as a practical example ofa fourth maintenance service, its service provision method will be setforth below.

Upon start-up and shut-down of the power plant's functional units, theoperation status must be monitored more carefully than in normaloperation events due to the fact that startup and shutdown processes ofa variety of types of facility equipment along with plant statevariations overlap together. Additionally, in the case of coalcombustion plants which are in the mainstream of thermal power plants inrecent years, a change in kind of coal used as raw fuel material canresult in a significant change in burning or combustion state dependingon coal's components and properties, which would affect the plantoperation in a various ways. Other factors affecting the operationinclude age changes of a plant per se. Although these are not alwaysregarded as operation failures or malfunctions, they call for adjustmentof control systems on a case-by-case basis. The “ordinary event service”is such that in cases where operation state monitor or “watchdog” isespecially required such as in the events of startup of the unitsinvolved, operation interruption or “shutdown,” coal kind change, andchange with age, monitoring and evaluation are remotely done by anoperator who is expected to act as the maintenance service provider.

FIG. 19 shows a process flow of a method for providing the “ordinaryevent service.” In case an operator in a power station judges that themaintenance service provider's plant operation monitoring and controlsystem evaluation is necessary due to the unit operation startup,shutdown, coal kind change and change with age, s/he inputs a monitorsearch request at the maintenance tool 2. Practical contents of theprocess flow of FIG. 19 will be explained with reference to FIGS. 20-22below.

FIG. 20 shows a sequence of exemplary operation display images forpreparation of such monitor search request at the maintenance tool 2.Upon selection of an icon of “Request Monitor Search” in the visualdisplay of the remote maintenance request menu 12, the screen changes tovisually indicate a monitor search request display 122. The powerstation operator inputs information including a monitor search contentand monitor search period and others and then performs data sendoperations thus causing the monitor search request data to be sent forthtoward the remote maintenance device 3 via the public communication line8. The maintenance tool 2 acquires process amount data (pressures andtemperatures) and control signal data (operation end instruction values)in accordance with the content of such monitor search request and thentransmits the data to the remote maintenance device 3 over the publiccommunication line 8. In responding thereto, the maintenance serviceprovider saves the received data and the monitor search request contentin the memory device of the remote maintenance device 3 for analyzationof such saved data at the remote maintenance device 3.

FIG. 21 shows a sequence of exemplary operation display images foranalysis of the ordinary event data at the remote maintenance device 3.When selecting “Data Search/Analyze” icon in the visual display ofordinary event service menu 14, the screen changes to present ordinaryevent data search/analysis display 141. With this visual display, themaintenance service provider commands to display a trend graph of thedata as received from the maintenance tool 2 along with the monitorsearch content and the like, then evaluates the data, and theninvestigates for determination of whether a need arises to modify orupdate the control parameter(s) or control circuitry. After havinganalyzed the data, the maintenance service provider prepares at theremote maintenance device 3 a monitor search report which summarizestherein data evaluation results and, if necessary, modified controlparameter(s) or control circuitry along with the ground(s) thereof, thens/he sends the report to the maintenance tool 2 via the publiccommunication line 8.

FIG. 22 shows a sequence of exemplary operation display images forpreparation of the monitor search report at the remote maintenancedevice 3. Upon selecting of “Form Report” icon in the ordinary eventservice menu display 14, the screen changes to visually indicate amonitor search report preparation display 142. With this image, themaintenance service provider prepares his or her report summarizingtherein monitor search contents and evaluation results thereof plus acontrol parameter change(s) or control circuitry change(s) in case suchis judged to be necessary. At the maintenance tool 2, upon receipt ofthe monitor search report, a guidance for updating a controlparameter(s) or control circuit(s) is visually displayed on the screenof monitor 23 in accordance with the control parameter/circuit changecontent as recited in the monitor search report, thus permitting anoperator in the power station to rewrite using the parameter onlinetuning function or control operation logic edit function of themaintenance tool 2 the object data being presently stored in the memorywithin the controlling controller 11 via the transfer device 24 and unitnetwork 7 in deference to the presently displayed guidance.Alternatively, if the tuning is directly set by a changeover switch orthe like to the state of allowance then the maintenance tool 2automatically operates to rewrite in online way the object data inaccordance with the update contents of the control parameter(s) orcontrol circuitry. In addition, at the maintenance tool 2, it performsprinting and/or saving tasks of the monitor search report data thusreceived.

It has been described that with the illustrative embodiment, it ispossible to promptly provide adequate maintenance services at low costsin routine inspection events and also in abnormality occurrence eventsthus improving the quality of maintenance services because of the factthat as far as the maintenance service provider is linked bycommunications lines with the maintenance tool in a power station, theuse of a remote maintenance device offering similar executable functionsto those of the maintenance tool makes it possible to provide from aremote cite various maintenance services including but not limited totest data summarization and evaluation results during routine inspectionprocedures and/or search and investigation results in abnormalityoccurrence events.

1. A thermal power plant maintenance service provision method using athermal power plant maintenance system comprising a control device forcontrol of plant equipment, a maintenance tool operatively coupled tosaid control device via a communication network for performingmaintenance of said control device, and a remote maintenance device,remote from said thermal power plant, communicatively connected to saidmaintenance tool, said method comprising: transmitting, from saidmaintenance tool, plant equipment data to said remote maintenancedevice; transmitting, from said remote maintenance device, report dataprepared by a maintenance service person based on the transmitted plantequipment data, including instructions for revising a control parameterof a control circuitry of said control device, to said maintenance tool;and saving said report data at said maintenance tool, wherein saidcontrol parameter is part of a control operation logic of the controlcircuitry and said control circuitry supports the control operationlogic.
 2. A plant maintenance service provision method using a plantmaintenance system comprising a control device for control of plantequipment, a maintenance tool operatively coupled to said control devicevia a communication network for performing maintenance of said controldevice and a remote maintenance device, remote from said plant,communicatively connected to said maintenance tool comprising:transmitting, from said maintenance tool, plant data to said remotemaintenance device; transmitting, from said remote maintenance device,report data based upon the transmitted plant data, includinginstructions for revising a control parameter of a control circuitry ofsaid control device to said maintenance tool; and saving said reportdata at said maintenance tool, wherein said control parameter is part ofa control operation logic of the control circuitry and said controlcircuitry supports the control operation logic.
 3. A plant maintenancesystem comprising: a control device controlling plant equipment; amaintenance tool operatively coupled to said control device via acommunication network performing maintenance of said control device; anda remote maintenance device, remote from said plant, receiving plantequipment data from said maintenance too and transmitting reportingdata, based on said receive plant equipment data, including instructionsfor revising a control parameter of a control circuitry of said controldevice to said maintenance tool, wherein said control parameter is partof a control operation logic of the control circuitry and said controlcircuitry supports the control operation logic.
 4. A plant maintenanceservice provision method using a plant maintenance system comprising acontrol device controlling an operation state and process amount ofplant equipment, a maintenance tool operatively coupled to said controldevice via a communication network performing maintenance of acontrolling controller built in said control device, and a remotemaintenance device, remote to said plant, communicatively connected tosaid maintenance tool, said method comprising: transmitting, from saidmaintenance tool, plant data to said remote maintenance device;transmitting, from said remote maintenance device, revision instructiondata describing a revision to be applied to a control parameter ofcircuitry in said controlling controller to said maintenance tool; andrevising said control parameter of said circuitry of said control deviceaccording to said revision instruction data from said maintenance tool,wherein said control parameter is part of a control operation logic ofthe circuitry of said control device and said circuitry of said controldevice supports the control operation logic.
 5. A plant maintenanceservice system, comprising: a control device to control an operationstate and process amount of plant equipment; a maintenance tool,operatively coupled to said control device via a communication network,to perform maintenance of a controlling controller built in said controldevice; and a remote maintenance device, remote from said plant, toreceive plant data from said maintenance tool and to transmit revisioninstruction data describing a revision to be applied to a controlparameter of circuitry in said controller, wherein said maintenance toolhas a function of revising of said control parameter of said circuitryof said control device according to said revision instruction data, saidcontrol parameter is part of a control operation logic of the circuitryof said control device and said circuitry of said control devicesupports the control operation logic.